A DLC (Diamond Like Carbon) film has a structure of diamond and graphite being mixed, a structure of an intermediate between the both, is high in hardness and is excellent in abrasion resistance, solid lubricity; thermal conductivity, and chemical stability, to thus be widely used as a protective film of various parts of a sliding member, a mold, cutting tools, an abrasion-resistant machine part, an abrasive, a magneto-optical part, and the like, for example.
As a film-forming method of the DLC film, two types of a PVD (Physical Vapor Deposition) method and a CVD (Chemical Vapor Deposition) method have been known mainly. When these PVD method and CVD method are compared, from the perspective that a film-forming rate of the CVD method is faster than that of the PVD method and the CVD method enables efficient film-forming on a material having a complicated shape, using the CVD method has become the mainstream.
For example, Patent Document 1 discloses a method for producing a DLC film by a plasma CVD method, in which a voltage to be applied to a substrate is set to a bipolar DC pulse voltage, a gas to be supplied into a chamber is set to a toluene-containing gas, and further the total gas pressure in the chamber is set to not less than 4 Pa and not more than 7 Pa. According to Patent Document 1, an intermediate layer can be formed by a PVD method and a DLC film can be formed by a plasma CVD method.